Abstract: Techniques have been developed whereby concurrency control mechanisms such as nested databases can be expressed in terms of operations implemented by various flexible transaction processing systems. For example, one such implementation of nested databases is particularly suitable for transaction processing systems that provides a lock delegation facility and which allow specification of ignore-conflict relationships between locking capabilities. By providing techniques that support movement of objects from a database to a subdatabase thereof, as well as termination (e.g., commit or abort) of transactions and databases (including subdatabases), transaction processing systems can provide advanced transaction models with unconventional concurrency control mechanisms. Some realizations allow specification of uses of parameters with lock modes and facilitate transformation of such uses into a form suitable for utilization in execution environments that support ignore-conflict relationships.

Abstract: A method and system for processing and managing requests for concurrent use of data. Nested databases are utilized in order to create different environments in which the data can be accessed and modified. For each transaction which is in existence, there is an indication or reference to a database or subdatabase associated with that transaction. There are also data structures which indicate, for each data item at issue, which database or subdatabase is associated with that item. The use of data structures relating the transactions, subdatabases, and data items allows the creation of spheres of control for the various transactions and subdatabases. Thus, data can be readily shared among a plurality of users. The creation of the subdatabases does not require plural copies of data and the database management system may be implemented using one copy of the data, although multiple copies may be utilized, if desired.

Abstract: A method, system, and collaborative user interface for creating a collaborative environment for users to work on shared resources on a computer network. Each resource is capable of being subdivided into sub-resources in a hierarchical manner, and each sub-resource is treated in a transactional way in the sphere of control to which it is delegated/copied, which ensures proper treatment with respect to the resource from which it originated. The method thus provides a powerful management system allowing a number of people to work simultaneously on various parts of the shared resources.